激光立体成形GH4169合金具有晶粒粗大且分布不均匀和孪晶界体积分数大等特点，在很大程度上影响了合金疲劳性能。采用热等静压处理对激光立体成形GH4169合金沉积态试块进行后续处理，并结合后续热处理，进一步提高材料的致密度和再结晶晶粒尺寸分布均匀性。结果显示，热等静压处理后合金的再结晶晶粒尺寸由50~500 μm变为100~200 μm，平均尺寸减小且分布更均匀，晶粒圆整度提高；合金中界面结构发生改变，特殊界面〈111〉60°孪晶界的数量明显减少；热等静压处理后激光立体成形GH4169合金的疲劳性能较未经热等静压处理试样有较大幅度提高，但仍低于锻件标准。

The fatigue property of laser solid forming (LSF) GH4169 superalloy is worse for the influences of the coarse and uneven distributed grains and the existence of large amount of twin boundaries. The post hot isostatic pressing (HIP) process is used to the LSF GH4169 superalloy sample to improve its high cycle fatigue property owing to the enhancement of density and the uniform of the grain structure, combined with the post heat treatment. The results show that the grains are refined to an average size of 100~200 μm from 50~500 μm and their spherical degrees are raised. The interface structure also changes and the volume fraction of 〈111〉60° twin boundary clearly decreases. HIP can effectively improve the high cycle fatigue property of LSF GH4169 superalloy, however, it is still lower than the standard value of forged GH4169.